“We continue to call [on] the Chinese authorities to grant Mr Liu full parole, and to release his wife Liu Xia from house arrest, and provide them with the protections and freedoms such as freedom of movement, and access to appropriate medical care that are consistent with China’s constitution, legal system and international commitments,” the embassy said in a statement.

The German foreign ministry source did not give details of the result of the German doctor’s examination, or say whether US doctors had seen Liu.

Liu, the 2010 winner of the Nobel Peace Prize, was sentenced to 11 years behind bars in 2009 for “inciting subversion of state power”. He had signed a petition known as “Charter 08” with other rights activists calling for sweeping political reforms in the country.

He was granted medical ­parole last month after he was diagnosed with the cancer in May. Liu Xia has been with him but friends said they could not visit or communicate with the couple.

Family friend Ye Du said a hospital insider told him that Liu was in a critical condition in the afternoon and all members of an emergency medical crew were ordered on standby in case his condition worsened.